Many mobile wireless devices now provide users with the capability to obtain media communication services over packet-based wireless networks. For example, many mobile devices are enabled to provide Voice-over-IP (VoIP). Wireless local area networks (WLANs), such as those defined by the IEEE 802.11 standard, are also becoming more common, especially on business or university campuses or other facilities in order to provide effective wireless coverage to a defined area.
A media service like VoIP operates over a packet-based network using a peer-to-peer connectionless protocol, such as real-time transport protocol (RTP), to exchange data packets between two or more termination points, for example, mobile devices. An RTP path is typically established through the wireless network (and, possibly, other connected networks) using a service set-up or control protocol, like session initiation protocol (SIP). Other control or set-up protocols may also be used to establish an RTP path, or other connectionless peer-to-peer transport path, to facilitate packet exchange for a media service.
A media service in which at least one of the termination points is a mobile device operating in a wireless network is prone to disruption as a result of the mobile device losing coverage. Coverage may be lost for a number of reasons, but most commonly because the mobile device roams into a region in which RF communications between the mobile device and a wireless network base station are interrupted, attenuated, interfered with, or otherwise disrupted. When the mobile device goes out-of-coverage, neither it nor the other termination point (which may also be a mobile device) is necessarily aware of the out-of-coverage condition at an application level. As a result, the service that was established between the two termination points continues, despite the fact that the devices cannot exchange data packets. Therefore the devices remain tied up by a stalled service application when they might otherwise establish other services. The devices may remain busy with the failed service until a user deems the service to have failed and manually initiates termination of the service.
It would be advantageous to provide for methods and devices that gracefully terminate services in response to out-of-coverage conditions without necessarily requiring manual user intervention.